# First Report and Molecular Confirmation of Chicken Proventricular Necrosis Virus Associated with Transmissible Viral Proventriculitis in Bangladesh

## TL;DR

This study confirms the presence of chicken proventricular necrosis virus in Bangladesh, linked to a disease causing poor growth and lesions in young chickens.

## Contribution

First molecular confirmation of CPNV-associated TVP in Bangladesh.

## Key findings

- CPNV was detected in proventricular samples from affected chickens in Bangladesh.
- Histopathology showed glandular damage and inflammation in the proventriculus.
- Phylogenetic analysis placed the Bangladeshi CPNV strain within known clades.

## Abstract

Transmissible viral proventriculitis (TVP) is an emerging disease among young chickens that causes poor growth, uneven body weight, and characteristic lesions in the proventriculus. Although TVP has been reported in several countries, information from South Asia remains scarce. In this study, two poultry flocks in Bangladesh showed growth retardation and proventricular enlargement, raising suspicion of TVP. Histopathology and molecular testing of proventricular samples from the affected birds confirmed proventriculitis and the presence of chicken proventricular necrosis virus (CPNV), the virus most strongly associated with TVP. These findings provide the first molecular evidence of CPNV-associated TVP in Bangladesh and emphasise the need for further surveillance to better understand the distribution and impact of the disease in the region.

Transmissible viral proventriculitis (TVP) is an emerging disease in chickens, linked to chicken proventricular necrosis virus (CPNV), a recently identified birnavirus. Here, we provide the first molecular confirmation of TVP in Bangladesh from a coloured meat-type parent stock (PS) flock, while documenting a contemporaneous white layer flock with consistent clinical signs and characteristic gross lesions. Affected birds exhibited growth retardation, diarrhoea, and increased mortality, alongside hallmark gross changes in proventricular enlargement and wall thickening. From the meat-type PS, proventricular samples were collected for histopathology and molecular diagnostics. Histological analysis revealed severe glandular epithelial damage, necrosis, mononuclear infiltration, epithelial hyperplasia, and metaplasia. Using RT-PCR on nucleic acid extracted from FTA card samples, CPNV was detected. In addition, infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), and avian reovirus (ARV) nucleic acids were also identified. The amplified CPNV VP1 fragment was sequenced, and phylogenetic analysis placed the Bangladeshi strain within clades of previously reported CPNV isolates. This study represents the first molecularly confirmed report of CPNV associated with TVP in Bangladesh, highlighting the need for active surveillance in commercial and breeder poultry flocks to understand the virus’s epidemiology and support the development of control strategies.